Insert clamping wedge and insert-detachable type cutter

ABSTRACT

An insert clamping wedge for clamp-fixing a cutting insert, seated in an insert attachment seat formed in a cutter body, to a recessed portion formed in the insert attachment seat is provided, the insert clamping wedge including: a wedge body, wherein the insert clamping wedge is pressed into the cutter body, wherein the wedge body includes a clamp surface which comes into close contact with the cutting insert and a wedge surface of which a gap between itself and the clamp surface becomes smaller in a press-insertion direction of the wedge body, and wherein the section perpendicular to the press-insertion direction of the wedge body from the wedge surface to the clamp surface being formed in a bell shape.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an insert clamping wedge (hereinafter,referred to as a clamp wedge) which is used to detachably clamp-fix acutting insert to an insert attachment seat of a cutter body in aninsert-detachable type cutter such as a face mill and also relates to aninsert-detachable type cutter which is mounted with the clamp wedge soas to attach the cutting insert thereto.

Priority is claimed on Japanese Patent Application No. 2008-88334, filedMar. 28, 2008, the content of which is incorporated herein by reference.

2. Description of Related Art

An insert-detachable type cutter using a clamp wedge is disclosed in,for example, Japanese Examined Patent Application Publication, SecondPublication No. H01-44443, Japanese Unexamined Patent Application, FirstPublication No. H01-295709, and PCT International Publication No. WO2008/023361. The insert-detachable type cutter includes a cutter body, acutting insert, and a clamp wedge which is used to fix the cuttinginsert to the cutter body. The cutter body is provided with an insertattachment seat and a recessed portion which communicates with theinsert attachment seat. The cutting insert is seated in the insertattachment seat. The clamp wedge is inserted into the recessed portion.The clamp wedge is pressed by a pressing member such as a clamp screw soas to be inserted into the cutter body along a wedge surface of theclamp wedge. At this time, the cuffing insert having a polygonal flatplate shape seated in the insert attachment seat is pressed into theinsert attachment seat in a thickness direction so as to be clamp-fixedthereto by means of a clamp surface of the clamp wedge. Here, thesurface of the clamp wedge is inclined so that the distance between thewedge surface and the surface of the clamp wedge becomes smaller in apress-insertion direction.

In order to reliably fix the cutting insert by means of the clamp wedge,it is necessary to ensure a large area of the clamp surface. However, inthe clamp wedge disclosed in Japanese Examined Patent ApplicationPublication, Second Publication No. H01-44443, Japanese UnexaminedPatent Applications First Publication No. H01-295709, and PCTInternational Publication No. WO 2008/023361, a section perpendicular tothe press-insertion direction is formed such that the clamp surface isformed in a square shape and the wedge surface is formed in asemicircular arc shape which has the same width as that of the squareshape and is smoothly connected to the square shape. That is, the clampwedge is formed in a semicircular arc shape (barrel roof shape or vaultshape). Accordingly, when the width of the clamp surface in the sectionincreases in order to increase the area of the clamp surface, the radiusof the semicircular arc shape of the wedge surface increases. That is,when the area of the clamp surface increases, the wedge body simplyincreases in size.

When the wedge body increases in size, the recessed portion of thecutter body mounted with the clamp wedge increases in size. On the otherhand, the distance between the recessed portion and the outer peripheralsurface of the cutter body becomes smaller. Accordingly, when the clampwedge is pressed so as to clamp the insert, the clamping strength maydeteriorate or the thinned portion may be deformed or damaged.

Recently, in such an insert-detachable type cutter, a so-called increasein the number of blades is required so as to realize the high efficiencyof processing by increasing the number of blades provided in the cutterbody. Accordingly, the number of the cutting inserts and the clampwedges for fixing the same tends to increase. However, in the case wherethe number of cutting blades increases, the gap between the insertattachment seat and the recessed portion is limited. As a result, it isdifficult to form the recessed portion having a large area describedabove.

SUMMARY OF THE INVENTION

The present invention is contrived in consideration of theabove-described circumstance. That is, an object of the presentinvention is to provide a clamp wedge and an insert-detachable typecutter capable of preventing a sectional area of a wedge body and arecessed portion perpendicular to a press-insertion direction of a wedgebody from excessively increasing, of maintaining the thickness of acutter body, and of ensuring a large area of a clamp surface byenlarging the width of the clamp surface.

In order to solve the above-described problems and to achieve theabove-described object, a clamp wedge according to the present inventionhas the following characteristic configuration. The clamp wedgeaccording to the present invention is an insert clamping wedge whichclamp-fixes a cutting insert, seated in an insert attachment seat formedin a cutter body, to the insert attachment seat. A wedge body pressedinto the cutter body is provided with a clamp surface which comes intoclose contact with the cutting insert and a wedge surface of which thegap between the wedge surface and the clamp surface becomes smaller in apress-insertion direction of the wedge body. An external shape of thewedge surface in a section perpendicular to the press-insertiondirection of the wedge body includes a protruded curve portion andrecessed curve portions of which the distance therebetween becomeslarger in a direction from both ends of the protruded curve portiontoward the clamp surface. That is, the section from the wedge surface tothe clamp surface is formed in a bell shape.

In an insert-detachable type cutter according to the present invention,the clamp wedge is mounted to the recessed portion, formed in the cutterbody so as to communicate with the insert attachment seat, in such amanner that the wedge surface is pressed by a pressing member so as tocome into slidable contact with an inner wall surface of the recessedportion.

In the clamp wedge and the insert-detachable type cutter according tothe present invention, the sectional shape perpendicular to thepress-insertion direction of the wedge body is formed in a bell shape.That is, in the wedge surface of the wedge body, both ends of theprotruded curve form a recessed curve to thereby form a narrowed shape.Accordingly, even when the width of the clamp surface increases toensure a large area, it is possible to prevent the sectional area of thewedge body and the recessed portion perpendicular to the press-insertiondirection from excessively increasing. As a result, it is possible tocope with an increase in the number of cutting blades by using the clampwedge according to the present invention. Also, in the insert-detachabletype cutter according to the present invention, the clamp wedgeaccording to the present invention is used. Accordingly, even when thenumber of cutting blades increases, it is possible to prevent the cutterbody from being deformed or damaged by maintaining the thickness in theperiphery of the recessed portion of the cutter body and to strongly fixthe cutting insert by improving the clamping strength.

Further, in the section perpendicular to the press-insertion direction,the wedge surface of the wedge body of the clamp wedge is formed by aregion from the protruded curve portion to at least the recessed curveportions in both ends thereof. That is, the gap between the wedgesurface and the clamp surface becomes smaller in the press-insertiondirection of the wedge body. With such a configuration, it is possibleto reliably apply the pressing force from both ends of the wedge surfaceto the opposite-side clamp surface by pressing the wedge body.Accordingly, in the clamp wedge according to the present invention, itis possible to strongly fix the cutting insert in a stabler manner.

Meanwhile, in order to prevent deterioration of the clamping strengthdescribed above in the circular cutter body of the insert-detachabletype cutter, the cutter body may have the following configuration. Thatis, in a section perpendicular to the press-insertion direction, each ofopening peripheries of the recessed portion of the cutter body areformed in a recessed surface which rises up in a direction opposite tothe press-insertion direction as the distance from the clamping wedge ina diameter direction of the cutter body becomes greater. Accordingly,even when the gap between the insert attachment seat and the recessedportion is limited due to the increase in the number of cutting blades,it is possible to ensure a large thickness in both ends of the peripheryof the recessed portion of the cutter body in the press-insertiondirection. As a result, it is possible to improve the clamping strengthby ensuring the rigidity of the periphery of the recessed portion of thecutter body.

In addition, when the recessed portion is located on the side of therake face of the cutting insert fixed to the insert attachment seat, theopening periphery of the recessed portion, of which rises up to beformed in a recessed surface shape, may be formed in a recessed curveshape. With such a configuration, it is possible to increase thecapacity of the chip pocket formed by the opening periphery and thewedge body by ensuring the rigidity of the cutter body as describedabove. Accordingly, it is possible to smoothly discharge small fragmentsproduced by the cutting blade of the cutting insert and the abrading therake face.

As described above, according to the present invention, it is possibleto maintain the small thickness of the cutter body by preventing thesectional area of the wedge body or the recessed portion from increasingeven in the insert-detachable type cutter having a plural of blades.Accordingly, according to the present invention, it is possible toprevent a deformation or damage of the cutter body and to improve theclamping strength. In addition, since it is possible to obtain the clampsurface having a large area by enlarging the width of a clamp surface ofthe clamp wedge, the cutting insert can be strongly fixed. As a result,it is possible to efficiently and highly precisely carry out a cuttingprocess in a stable manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an insert-detachable type cutteraccording to an embodiment of the present invention when viewed from thefront-end outer peripheral side of a cutter body 1.

FIG. 2 is an enlarged perspective view showing a front-end outerperipheral portion of the cutter body 1 according to the embodimentshown in FIG. 1 when viewed from the front end side thereof.

FIG. 3 is an enlarged view showing the periphery of an insert attachmentseat 4, a chip pocket 5, and a recessed portion 6 according to theembodiment shown in FIG. 1 when viewed along the central axis of a screwhole 6C.

FIG. 4 is an enlarged new showing the periphery of the insert attachmentseat 4, the chip pocket 5, and the recessed portion 6 according to theembodiment shown in FIG. 1 when viewed in a direction parallel to abottom surface 4A of the insert attachment seat 4 and perpendicular tothe central axis of the screw hole 6C.

FIG. 5 is a perspective view showing a clamp wedge 10 according to theembodiment of the present invention.

FIG. 6A is a view showing the clamp wedge 10 according to the embodimentshown in FIG. 5 when viewed along the central axis C of a screw hole 13in an end surface 12A.

FIG. 6B is a view showing the clamp wedge 10 according to the embodimentshown in FIG. 5 when viewed in a direction parallel to a clamp surface14 and perpendicular to the central axis C.

FIG. 6C is a view showing the clamp wedge 10 according to the embodimentshown in FIG. 5 when viewed in a direction perpendicular to the centralaxis C and facing the clamp surface 14.

FIG. 7 is a view showing the clamp wedge 10 according to the embodimentis inserted into the recessed portion 6 shown in FIG. 4.

FIG. 8 is a view shown the clamp wedge 10 according to the embodiment isinserted into the recessed portion 6 shown in FIG. 3.

FIG. 9A is a view showing a clamp wedge 20 according to a modifiedexample of the embodiment show in FIG. 5 when viewed along the centralaxis C of the screw hole 13 in a section 12A.

FIG. 9B is a view showing the clamp wedge 20 according to the modifiedexample of the embodiment shown in FIG. 5 when viewed in a directionparallel to the clamp surface 14 and perpendicular to the central axisC.

FIG. 9C is a view showing the clamp wedge 20 according to the modifiedexample of the embodiment shown in FIG. 5 when viewed in a directionperpendicular to the central axis C and facing the clamp surface 14.

FIG. 10 is a perspective view showing a clamp wedge 30 according toanother modified example of the embodiment shown in FIG. 5.

FIG. 11 is a perspective view showing the insert-detachable type cutteraccording to the embodiment of the present invention attached with thecutting insert when viewed from the front-end outer peripheral side ofthe cutter body 1.

FIG. 12 is an enlarged perspective view showing the front-end outerperipheral portion of the cutter body 1 according to the embodimentshown in FIG. 11 when viewed from the front end side thereof.

FIG. 13 is an enlarged view shown the periphery of a chip pocket 5, aclamp wedge 10, a clamp screw 11, and a cutting insert 21 according tothe embodiment shown in FIG. 11 when viewed along the central axis ofthe clamp screw 11.

FIG. 14 is an enlarged view showing the periphery of the chip pocket 5,the clamp wedge 10, the clamp screw 11, and the cutting insert 21according to the embodiment shown in FIG. 11 when viewed in a directionperpendicular to the central axis of the clamp screw 11.

FIG. 15 is a perspective view showing the cutting insert attached to thecutter body 1 according to the embodiment shown in FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 14 are views showing a clamp wedge and an insert-detachabletype cutter according to an embodiment of the present invention. In theinsert-detachable type cutter according to this embodiment, a cutterbody 1 is formed of steel or the like so as to have a substantially discshape as shown in FIG. 1. The rear end side (the upper side of FIG. 1)of the cutter body 1 in a central axial direction is formed as anattachment portion 2 which is attached to a main shaft of a machinetool. The front end side (the lower side of FIG. 1) of the cutter body 1is formed as a blade portion 3 having a diameter larger than that of theattachment portion 2 by one level. The cutter body 1 is configured torotate about the central axis in a cutter rotation direction T so as tobe used in which a workpiece is cut.

The front-end outer peripheral side of the blade portion 3 is providedwith an insert attachment seat 4 which is formed by cutting the rear-endinner peripheral side of the blade portion 3 so as to fix a cuttinginsert 21 thereto in a seated state as described below. Also, thefront-end outer peripheral side thereof is provided with a chip pocket 5and a recessed portion 6 which communicate with each other in the insertattachment seat 4 in the cutter rotation direction T. Plural groups eachincluding the insert attachment seat 4, the chip pocket 5, and therecessed portion 6 are arranged in a circumferential direction of theblade portion 3 so as to have a predetermined interval therebetween. Aclamp wedge 10 according to this embodiment is inserted into therecessed portion 6 so as to be pressed toward the rear-end innerperipheral side of the cutter body 1 by means of a clamp screw 11(pressing member 11) of which both ends are provided with a male screwportion. Accordingly, the cutting insert 21 is pressed into the insertattachment seat 4 so as to be clamp-fixed thereto.

FIGS. 11 and 14 show the insert-detachable type cutter in which eachcutting insert 21 is accommodated in each insert attachment seat 4 andis pressed by each clamp wedge 10 so as to be clamped thereto.

The cutting insert attached to the insert-detachable type cutteraccording to this embodiment is formed of a hard material such as hardmetal so as to have a regular polygonal (for example, a regularheptagonal) flat plate shape. An example of the cutting insert is shownin FIG. 15. The cutting insert 21 having a flat plate shape shown inthis example has a configuration in which both side surfaces are formedparallel to each other in a substantially regular heptagonal shape, oneside surface is formed as a rake face 23, and then the other sidesurface is formed as a seat surface 22 facing the insert attachment seat4. A cutting blade is formed in a side ridge of the rake face. Thecutting insert 21 is formed as a hollow insert in which a circular holeis formed in the center of the rake face in a sectional view, and therake face is formed as a surface having a hole formed therethrough.

The insert attachment seat 4, on which the hollow cutting insert 21 isseated, includes a flat bottom surface 4A facing the cutter rotationdirection T and a pair of wall surfaces 4B uprightly formed from theside ridges on the inner peripheral side and the rear end side of thecutter body 1 of the bottom surface 4A. Two side surfaces of the hollowinsert 21 respectively come into contact with the wall surfaces 4B so asto allow the rake face 23 to face the cutter rotation direction T. Atthe same time, the seat surface 22 of the hollow insert comes into closecontact with the bottom surface 4A, and the hollow insert is seated inthe insert attachment seat 4. At this time, for example, in the casewhere the insert-detachable type cutter is a face mill, one of sevencutting blades of the cutting insert 21 is located on one planeperpendicular to the central axis of the face mill.

As shown in FIG. 4, the chip pocket 5 is formed to be widened toward theouter peripheral side of the cutter body 1 (the upper side of FIG. 4) inthe cutter rotation direction T. The recessed portion 6 is opened at thecenter portion of the bottom surface 5A of the chip pocket 5 facing theouter peripheral side of the cutter body 1 so as to have a gap withrespect to the peripheral surface of the cutter body 1. Also, therecessed portion 6 extends to the rear-end inner peripheral side of thecutter body 1 so as to communicate with the insert attachment seat 4.

The recessed portion 6 includes a bottom surface 6A which is located onthe rear-end inner peripheral side of the cutter body 1 and an innerwall surface 6B which extends from the bottom surface 5A of the chippocket 5 toward the bottom surface 6A and the rear-end inner peripheralside of the cutter body 1. The bottom surface 6A is provided with ascrew hole 6C into which the male screw portion of one end of the clampscrew 11 is threaded. The screw hole 6C faces the rear-end innerperipheral side of the cutter body 1 and the bottom surface 4A of theinsert attachment seat 4 so as to extend in a direction in which thepair of wall surfaces 4B intersects each other. The inner wall surface6B extends in parallel to the central axis of the screw hole 6C. Thedirection facing the inside (rear-end inner peripheral side) of thecutter body 1 along the central axis of the screw hole 6C corresponds tothe direction in which the clamp wedge 10 according to this embodimentis pressed. The recessed portion 6 is formed in a complementary shapewith respect to the shape of the clamp wedge 10.

In the clamp wedge 10 inserted and pressed into the recessed portion 6,a wedge body 12 is formed of steel or the like. As shown in FIGS. 5 and6A to 6C, the clamp wedge 10 is formed in a hollow piece shape. Thehollow portion is formed as a screw hole 13 into which the male screwportion of the other end of the clamp screw 11 is threaded. The wedgebody 12 is inserted into the recessed portion 6 in such a manner thatone end surface 12A faces the front-end outer peripheral side (frontside) of the cutter body 1 and the other end surface 12B faces thebottom surface 6A of the recessed portion 6. Then, the clamp wedge 10 ispressed into the recessed portion 6 in a direction toward the rear-endinner peripheral side of the cutter body 1 by respectively threading themate screw portions of both ends of the clamp screw 11 into the screwhole 13 of the clamp wedge 10 and the screw hole 6C. Accordingly, in theclamp wedge 10, the direction from the end surface 12A to the endsurface 12B along the central axis C of the screw hole 13 corresponds tothe press-insertion direction.

One of side surfaces extending between both end surfaces 12A and 12B ofthe wedge body 12 is formed as a clamp surface 14 which comes into closecontact with the rake face of the hollow insert in a direction towardthe insert attachment seat 4 when the clamp wedge 10 is pressed into therecessed portion 6. In this embodiment, a protrusion 15 is formed at thecenter of the clamp surface 14. At the boundary between the protrusion15 and the clamp surface 14, a recessed groove portion 14A is formed soas to be slightly recessed from the clamp surface 14. In thisembodiment, the whole surface of the clamp surface 14 except for theprotrusion 15 and the recessed groove portion 14A is formed in aninclined plane shape in which the inclined plane becomes closer to thecentral axis C of the screw hole 13 in a direction toward the endsurface 12A at an inclined angle formed between the central axis of thescrew hole 6C and the bottom surface 4A of the insert attachment seat 4.The inclined plane shape is formed so as to surround the protrusion 15and the recessed groove portion 14A.

In addition, in this embodiment, the surface of the protrusion 15 isformed in a spherical shape. The section taken along the clamp surface14 and the section parallel to the clamp surface 14 are formed in acircular shape. Here, as shown in FIG. 6, the protrusion height of theprotrusion 15 from the clamp surface 14 is set to be sufficientlysmaller than the radius of the circle formed by the protrusion 15 in thesection taken along the clamp surface 14. At the same time, the radiusof the circle in the section is set to be smaller than the radius of thecircle formed by the opening of the rake face of the hollow insert. Thatis, the protrusion 15 is configured to be accommodated in the hole ofthe rake face of the hollow insert when the clamp wedge 10 is pressedinto the recessed portion 6 so that the clamp surface 14 comes intoclose contact with the perforated surface of the hollow insert.

On the other hand, the side surface of the wedge body 12 facing theopposite side of the clamp surface 14 is formed as a wedge surface 16.The wedge surface 16 is formed as a surface (a contact surface in amovable state) which comes into slidable contact with the inner wallsurface 6B when the clamp wedge 10 is pressed into the recessed portion6 of the cutter body 1. The wedge surface 16 extends in a directionparallel to the central axis C between both end surfaces 12A and 12B sothat the section perpendicular to the central axis C, that is, thesection perpendicular to the press-insertion direction is uniform. Aside surface is formed between the wedge surface 16 and the clampsurface 14 so as to be perpendicular to the clamp surface 14 and to beparallel to the central axis C, and the clamp surface 14 is inclinedwith respect to the central axis C. Accordingly, the width of the sidesurface becomes narrow in a direction toward the end surface 12B.

In addition, a protruded curve portion 16A and recessed curve portions16B are formed in a section of the wedge surface 16 which isperpendicular to the press-insertion direction. The protruded curveportion 16A is a protruded curve portion (barrel roof shape parts orvault shape parts) which forms a protruded curve having a semicirculararc shape (a half of a circular arc) with respect to the central axis C.Each recessed curve portion 16B is a recessed curve portion which facesthe clamp surface 14 and is formed in a recessed curve such as arecessed circular arc which smoothly connects both ends of the protrudedcurve portion 16A to the protruded curve portion 16A. The recessed curveportions 16B widen toward the clamp surface 14 in a direction in whichthe clamp surface 14 extends in the section (a vertical direction ofFIG. 6A and a horizontal direction of FIG. 6C) and is connected to theside surface. Accordingly, in this embodiment, the shape perpendicularto the press-insertion direction of the wedge body 12 is a bell shapeshown in FIG. 6A.

In the clamp wedge 10 according to the present invention, a ratiobetween the width of the clamp surface (β of FIG. 6A) and the diameter(α of FIG. 6A) of the semicircular arc about the central axis C of theprotruded cure portion 16A is not limited, but is desirably equal to ormore than 60% and less than 100%, and more desirably equal to or morethan 70% and equal to or less than 80%.

The sectional shape of the inner wall surface 6B of the recessed portion6 of the cutter body has a recessed-protruded shape opposite to arecessed-protruded shape of the wedge surface 16, the inner wall surface6B being configured to come into contact with the wedge surface 16 whenthe clamp wedge 10 is pressed into the recessed portion 6. That is, thesectional shape of the inner wall surface 6B includes a recessed curveportion which forms a recessed curve having a semicircular arc shape (ahalf of a circular arc) about the central axis of the screw hole 6C anda protruded curve portion which forms a protruded curve such as aprotruded circular arc smoothly connecting both ends of the recessedcurve portion to the recessed curve portion so as to be widened in adirection toward the insert attachment seat 6.

The bottom surface 5A of the chip pocket 5 of the cutter body 1 isformed in a shape (a recessed surface shape or a bowl shape) which risesup in a direction opposite to the press-insertion direction, the bottomsurface 5A corresponding to the periphery of the opening where therecessed portion 6 is opened. That is, in the section perpendicular tothe press-insertion direction, that is, the section perpendicular to thecentral axis of the screw hole 6C, the bottom surface 5A is formed in arecessed surface shape which rises up in a direction (the front side ofFIGS. 3 and 8) opposite to the press-insertion direction as the distancefrom the clamping wedge 10 in a diameter direction of the cutter bodybecomes greater, that is, the bottom surface 5A toward both ends in anextension direction of the clamp surface 14 of the clamp wedge 10pressed into the recessed portion 6, or direction toward both sides ofthe bottom surface 4A of the insert attachment seat 4 extending in thesame section (a vertical direction of FIGS. 3 and 8).

In this embodiment, the recessed surface formed by the bottom surface 5Ais formed in a recessed curve surface shape. That is, the bottom surface5A on the side of the recessed portion 6 is formed in a recessed curveshape in the section including the central axis of the screw hole 6C andperpendicular to the bottom surface 4A of the insert attachment seat 4.At the same time, the bottom surface 5A is formed in a recessed curvesurface shape which rises up to the front-end outer peripheral side ofthe cutter body 1 so as to be connected to the peripheral surface of thecutter body 1 as the bottom surface 5A becomes closer to the rear-endouter peripheral side and the front-end inner peripheral side of thecutter body 1 in a direction perpendicular to the plane forming thesection (see FIG. 4).

The hollow insert is attached to the insert-detachable type cutterhaving the above-described configuration. First, the wedge surface 16comes into slidable contact with the inner wall surface 6B so as toinsert the clamp wedge 10 into the recessed portion 6. Subsequently, theclamp screw 11 is threaded into the screw hole 13 of the wedge body 12and the screw hole 6C of the recessed portion 6 so as to temporarily fixthe clamp wedge 10 to the cutter body 1. Subsequently, the hollow insertis seated in the insert attachment seat 4 as described above.Subsequently, the clamp screw 11 is threaded again so as to press theclamp wedge 10 into the recessed portion 6. At this time, the protrusion15 of the clamp wedge 10 is accommodated in the hole of the hollowinsert, and the clamp surface 14 comes into close contact with theperforated surface so as to press the hollow insert into the bottomsurface 4A of the insert attachment seat 4. Accordingly, the hollowinsert is fixed in a clamped state. In addition, at this time, theprotrusion 15 may come into contact with the opening peripheral edge ofthe hole so as to draw the hollow insert in a direction in which thepair of wall surfaces 4B intersects each other.

The clamp wedge 10 which clamps the hollow insert is formed in a bellshape. That is, the section perpendicular to the press-insertiondirection of the wedge body 12 is formed in a bell shape including theprotruded curve portion 16A in which the wedge surface 16 on theopposite side of the clamp surface 14 forms a protruded curve having asemicircular arc shape and the pair of recessed curve portions 16B whichforms a recessed curve shape from both ends thereof so that the widththerebetween becomes large. With such a configuration, it is possible toensure a large area of the clamp surface 14 without excessivelyincreasing a sectional area of the wedge body 12 and the recessedportion 6 of the cutter body 1, the sectional area being perpendicularto the press-insertion direction.

In the case where such a clamp wedge is used, it is possible to clampthe cutting insert in the larger area. At the same time, it is possibleto improve the attaching rigidity of the clamp wedge 10 by enlarging thedistance between the surface of the cutter body 1 and the inner wallsurface 6B of the recessed portion 6. Accordingly, it is possible toimprove the clamping strength of the hollow insert and thus to highlyprecisely carry out the cutting process in a stable manner. In addition,since the sectional area of the recessed portion 6 does not excessivelyincrease, it is possible to cope with an increase in the number ofblades of the cutter body 1. Accordingly, since deformation or damagedoes not occur in the cutter body 1 during a clamping operation evenwhen the number of blades increases, it is possible to reliably carryout the efficient cutting process by means of plural blades.

Particularly, in this embodiment, the region from the protruded curveportion 16A to the recessed curve portions 16B of both ends thereof isformed as the wedge surface 16 as described above. In addition, eachrecessed curve portion 16B is inclined in a direction from the endsurface 12A of the wedge body 12 to the end surface 12B, that is, thepress-insertion direction so that a gap between itself and the clampsurface 14 becomes small. Accordingly, it is possible to reliably applythe pressing force to both widened side portions of the clamp surface 14on the under side of the recessed curve portion 16B. Accordingly, it ispossible to further strongly clamp-fix the cutting insert, and thus tohighly precisely carry out the cutting process in a stabler manner.

Meanwhile, in the insert-detachable type cutter according to thisembodiment, the bottom surface 5A of the chip pocket 5 is formed in arecessed surface shape, the bottom surface 5A corresponding to theperiphery of the opening where the recessed portion 6 of the cutter body1 is opened. That is, in a section perpendicular to the press-insertiondirection, the bottom surface 5A is formed in a recessed surface shapewhich rises up in a direction opposite to the press-insertion directionas the distance from the clamping wedge 10 in a diameter direction ofthe cutter body becomes greater. For this reason, even when the gapbetween groups each having the insert attachment seat 4, the chip pocket5, and the recessed portion 6 is limited to be small due to an increasein the number of blades, it is possible to ensure a large thickness ofthe cutter body 1 in the periphery of the recessed portion 6.Accordingly, it is possible to improve the rigidity in the periphery ofthe recessed portion 6. As a result, it is possible to strongly carryout the insert attaching operation in a stable manner by reliablyensuring the clamping strength.

In the recessed surface formed by the bottom surface 5A of the chippocket 5, for example, a section perpendicular to the plane includingthe central axis of the screw hole 6C and perpendicular to the bottomsurface 4A of the insert attachment seat 4 may be formed in a V-shape.In this embodiment, in the same section, the bottom surface 5A on theside of the recessed portion 6 forms the most recessed curve so as torises up in a direction opposite to the press-insertion direction as thedistance from the clamping wedge (10, 20, 30) in a diameter direction ofthe cutter body becomes greater, that is, toward the rear-end outerperipheral side and the front-end inner peripheral side of the cutterbody 1. With such a configuration, it is possible to increase thecapacity of the chip pocket 5 compared with the case where the sectionis formed in a V-shape as described above. Accordingly, in theinsert-detachable type cutter according to this embodiment, it ispossible to reliably accommodate small fragments produced by the cuttingblade of the cutting insert in the chip pocket 5 and to smoothlydischarge the small fragments. That is, in the insert-detachable typecutter according to this embodiment, it is possible to efficiently carryout the cutting process in a more stable manner.

Further, in the clamp wedge 10 according to this embodiment, the clampsurface 14 is provided with the protrusion 15 which is accommodated inthe hole of the hollow insert. Upon performing a corner change operationof the insert due to the abrasion of the cutting blade after the clampedhollow insert is used for a cutting process, first, the clamp screw 11is slightly loosened so as to release the pressed state of the hollowinsert. Subsequently, in the range that the protrusion 15 isaccommodated in the hole of the hollow insert 21 so as to maintain theengagement therebetween, the clamp wedge 10 and the hollow insert aredrawn out to the rear side in the press-insertion direction so as todeviate from each other. At this time, the hollow insert engages withthe protrusion 5 so as to be rotatable about the protrusion 15 whilebeing prevented from separating from the insert attachment seat 4.

Subsequently, in this state, the hollow insert is rotated so that thecutting blade to be used faces a predetermined direction. Subsequently,the insert is seated again in the insert attachment seat 4, and isclamped by threading the clamp screw 11 thereinto. Accordingly, forexample, even when the insert-detachable type cutter is a face mill orthe like and is mounted to a main shaft of a machine tool so that theinsert attachment seat 4 faces downward, it is possible to carry out thecorner change operation without dropping the hollow insert. For thisreason, in the lamp wedge 10 and the insert-detachable type cutteraccording to this embodiment, an operator does not have to rotate theinserts individually while pressing the insert by hand so as not to bedropped or an operator does not have to separate the cutter body 1 fromthe main shaft so as to carry out the corner change operation.Accordingly, even when the cutter has a plural of blades, inserts, andclamp wedges 10, it is possible to easily carry out the corner changeoperation in a short amount of time and to promptly resume the cuttingprocess. As a result, it is possible to improve the working efficiencyor the economical efficiency by shortening the overall processing time.

In addition, in this embodiment, since the protrusion 15 is formed in aspherical shape, the protrusion 15 is not crushed even when the cornerchange operation is repeated. At the same time, in this embodiment, itis possible to ensure a large gap between the hole and the protrusion insuch a manner that the clamp wedge 10 is made to recede along the innerwall surface 6B of the recessed portion 6 as described above so as tohave a slight gap between the clamp surface 14 and the perforatedsurface of the hollow insert. Accordingly, since the insert is easilyrotated, it is further possible to simply carry out the corner changeoperation.

The protrusion 15 may be formed in a shape in which the corner changeoperation can be carried out by allowing the hollow insert to berotatable about the protrusion 15 when the clamp wedge 10 and the hollowinsert are drawn out to the rear side in the press-insertion directionin a range that the engagement between the protrusion 15 and the hole ismaintained. For example, the protrusion 15 may be formed in a conicalshape or a conical trapezoid shape. In addition, the hollow insert maynot be formed in a regular polygonal flat plate shape so long as theside ridge of the surface having a hole formed therethrough is providedwith plural cutting blades of which the corners can be changed. Forexample, the hollow insert may be as a disc-shaped hollow insert. Inaddition, the hole of the hollow insert may be a perforation hole whichis formed through the surface having the hole and the opposite surfacethereof. Alternatively, the hole may not be a perforation hole.

Incidentally, in the clamp wedge 10 according to this embodiment, theperiphery of the protrusion 15 is surrounded by the clamp surface 14 viathe recessed groove portion 14A. For example, like a clamp wedge 20according to a modified example shown in FIG. 9, the recessed grooveportion 14A may extend to the edge of the clamp surface 14 so as to beopened from the edge. In addition, in the modified example shown in FIG.9 or another modified example shown FIG. 10 described below, the samereference numerals are given to the same parts as those of the clampwedge 10 according to the above-described embodiment, and thedescription thereof will be omitted.

In the case where the recessed groove portion 14A is formed like amodified example shown in FIG. 9, the clamp surface 14 is formed in aU-shape as shown in FIG. 9C. Accordingly, it is possible to carry out afinishing process in such a manner that a finishing tool such as agrinding tool or a finishing end mill used upon smoothly finishing theclamp surface 14 moves once along the U-shape without a locus overlap.That is, in a portion where the finishing tool advances to the clampsurface 14 and a portion where the fishing tool recedes from the clampsurface 14, the finishing surfaces thereof do not overlap with eachother. Accordingly, it is possible to reliably allow the clamp surface14 to come into close contact with the perforated surface of the hollowinsert without a minute step formed between the finishing surfaces inthe overlapping portions.

However, in the clamp wedge and the insert-detachable type cutteraccording to the invention, the protrusion 15 or the recessed grooveportion 14A may not be formed in the clamp surface 14. That is, like theclamp wedge 30 according to another modified example shown in FIG. 10,the whole clamp surface 14 may be formed in a plane shape in which a gapbetween the clamp surface 14 and the wedge surface 16 becomes small inthe press-insertion direction. According to the clamp wedge 30, it ispossible to carry out the clamping operation in a stable manner byfurther enlarging the contact area between the clamp surface 14 and thecutting insert, and to clamp the cutting insert without a hole insteadof the hollow insert.

In the clamp wedge 10 of the above embodiments, the protruded curveportion 16A of the wedge surface 16 has a semicircular shape in a crosssection perpendicular to the central axis C. The protruded curve portion16A may be formed a arc shape having a central angle less than 180° withrespect to the central axis C, for example, the central angle may be 45°or the like. In addition, the protruded curve need not be formed the arcshape, the protruded curve may have an elliptical-shaped cross section.

While preferred embodiment of the present invention have been describedand illustrated above, it should be understood that these are exemplaryof the present invention and are not to be considered as limiting.Additions, omissions, substitutions, and other modifications can be madewithout departing from the spirit or scope of the present invention.Accordingly, the present invention is not to be considered as beinglimited by the foregoing description, and is only limited by the scopeof the appended claims.

1. An insert clamping wedge for clamp-fixing a cutting insert, seated inan insert attachment seat formed in a cutter body, to a recessed portionformed in the insert attachment seat, the insert clamping wedgecomprising: a wedge body, wherein the insert clamping wedge is pressedinto the cutter body, wherein the wedge body includes a clamp surfacewhich comes into close contact with the cutting insert and a wedgesurface of which a gap between itself and the clamp surface becomessmaller in a press-insertion direction of the wedge body, and wherein anexternal shape of the wedge surface in a section perpendicular to thepress-insertion direction of the wedge body includes a protruded curveportion and a distance between recessed curve portions of which a widthbecomes larger in a direction from both ends of the protruded curveportion toward the clamp surface, the section from the wedge surface tothe clamp surface being formed in a bell shape.
 2. The insert clampingwedge according to claim 1, wherein in the section perpendicular to thepress-insertion direction of the wedge body, the wedge surface is formedby a region from the protruded curve portion to at least the recessedcurve portions in both ends thereof.
 3. An insert-detachable type cuttercomprising: a circular cutter body provided with recessed insertattachment seats which are formed in a circumferential direction at apredetermined interval so as to respectively seat cutting insertstherein and a recessed portion which is formed adjacent to each insertattachment seat; an insert clamping wedge which is accommodated in eachrecessed portion and is pressed into a bottom of the recessed portion soas to press-fix the cutting insert to the insert attachment seat; and apressing member which presses the insert clamping wedge into the bottomof the recessed portion, wherein the insert clamping wedge is the insertclamping wedge according to claim 1, and wherein the recessed portion isformed in a complementary shape with respect to the shape of the insertclamping wedge.
 4. The insert-detachable type cutter according to claim3, wherein in a section perpendicular to the press-insertion direction,each of opening peripheries of the recessed portion of the cutter bodyare formed in a recessed surface which rises up in a direction oppositeto the press-insertion direction as the distance from the clamping wedgein a diameter direction of the cutter body becomes greater.
 5. Theinsert-detachable type cutter according to claim 4, wherein the openingperiphery of the recessed portion is formed in a recessed curve surfaceshape.
 6. An insert-detachable type cutter comprising: a circular cutterbody provided with recessed insert attachment seats which are formed ina circumferential direction at a predetermined interval so as torespectively seat cutting inserts therein and a recessed portion whichis formed adjacent to each insert attachment seat; an insert clampingwedge which is accommodated in each recessed portion and is pressed intoa bottom of the recessed portion so as to press-fix the cutting insertto the insert attachment seat; and a pressing member which presses theinsert clamping wedge into the bottom of the recessed portion, whereinthe insert clamping wedge is the insert clamping wedge according toclaim 2, and wherein the recessed portion is formed in a complementaryshape with respect to the shape of the insert clamping wedge.
 7. Theinsert-detachable type cutter according to claim 6, wherein in a sectionperpendicular to the press-insertion direction, each of openingperipheries of the recessed portion of the cutter body are formed in arecessed surface which rises up in a direction opposite to thepress-insertion direction as the distance from the clamping wedge in adiameter direction of the cutter body becomes greater.
 8. Theinsert-detachable type cutter according to claim 7, wherein the openingperiphery of the recessed portion is formed in a recessed curve surfaceshape.